Interlocking system and method for joysticks in a catheter procedure system

ABSTRACT

An interlocking system for a joystick in a catheter procedure system includes a joystick configured to generate a first voltage output signal based on a linear activation of the joystick and a second voltage output signal based on a rotational activation of the joystick. A joystick cover is disposed over the joystick and includes an upper portion having an electrode plating on an inner surface of the upper portion and a lower portion having an inner surface. A capacitive touch detection circuit is coupled to the electrode plating of the upper portion of the joystick cover and is mounted on the inner surface of the lower portion of the joystick cover. The capacitive touch detection circuit is configured to detect a proximal change in capacitance in the electrode plating of the upper portion of the joystick cover and to generate a touch output signal to indicate whether a change in capacitance has been detected. A signal enable circuit is coupled to the joystick and the capacitive touch detection circuit and is configured to generate a linear enable voltage output signal and a rotational enable voltage output signal based on whether a change in capacitance has been detected.

FIELD OF THE INVENTION

The present invention relates generally to the field of catheter systemsfor performing therapeutic procedures and in particular, to aninterlocking system and method for joysticks in a catheter proceduresystem.

BACKGROUND OF THE INVENTION

Catheters may be used for many medical procedures, including inserting aguide wire, delivering a stent and delivering and inflating a balloon.Catheterization procedures are commonly performed for diagnosis andtreatment of diseases of the heart and vascular systems. Thecatheterization procedure is generally initiated by inserting a guidewire into a blood vessel in the patient's body. The guide wire is thenadvanced to the desired location, most commonly in one of the heartvessels or elsewhere in the vascular system. At this point, a catheteris slid over the guide wire into the blood vessel and/or heart. In someprocedures, the catheter is a balloon catheter or stent delivery systemthat when deployed at the site of the lesion allows for increased bloodflow through the portion of the coronary artery that is affected by thelesion.

For manual insertion of a guide wire, the physician applies torque andaxial push force on the proximal end of a guide wire to effect tipdirection and axial advancement at the distal end. Robotic catheterprocedure systems have been developed that may be used to aid aphysician in performing a catheterization procedure such as apercutaneous coronary intervention (PCI). The physician uses a roboticsystem to precisely steer a coronary guide wire, balloon catheter orstent delivery system in order to, for example, widen an obstructedartery. In order to perform PCI, the distal tip of a guide wire must benavigated through coronary anatomy past a target lesion. While observingthe coronary anatomy using fluoroscopy, the physician manipulates theproximal end of the guide wire in order to direct the distal tip intothe appropriate vessels toward the lesion and avoid advancing into sidebranches.

A robotic catheter procedure system includes various user input deviceand drive mechanisms to drive various elongated medical devices (e.g.,guide wire, guide catheter, working catheter) used in catheterizationprocedures to provide linear and rotational movement of the elongatedmedical device. The user input devices may include analog joysticks thatare used by an operator of the catheter procedure system to, forexample, advance, retract and rotate a percutaneous device, such as aguide wire, a guide catheter or a working catheter. A joystick mayexperience a fault or failure (e.g., the joystick may be stuck in an“on” state) that may cause a percutaneous device to move in anunexpected manner or may cause the unintended actuation of thepercutaneous device when the user is not touching the joystick.

It would be desirable to provide an interlocking system and method forjoysticks in a catheter procedure system that provides a single faultsafe joystick interface and that provides faster disabling time forhalting the motion of the manipulated percutaneous device,

SUMMARY OF THE INVENTION

In accordance with an embodiment, an interlocking system for a joystickin a catheter procedure system, the interlocking system includes ajoystick configured to generate a first voltage output signal based on alinear activation of the joystick and a second voltage output signalbased on a rotational activation of the joystick, a joystick coverdisposed over the joystick and comprising an upper portion having anelectrode plating on an inner surface of the upper portion and a lowerportion having an inner surface, a capacitive touch detection circuitcoupled to the electrode plating of the upper portion of the joystickcover, the capacitive touch detection circuit mounted on the innersurface of the lower portion of the joystick cover and configured todetect a proximal change in capacitance in the electrode plating of theupper portion of the joystick cover and to generate a touch outputsignal to indicate whether a change in capacitance has been detected,and a signal enable circuit coupled to the joystick and the capacitivetouch detection circuit, the signal enable circuit configured togenerate a linear enable voltage output signal and a rotational enablevoltage output signal based on whether a change in capacitance has beendetected.

In accordance with another embodiment, a catheter procedure systemincludes a bedside system having a percutaneous device and at least onedrive mechanism coupled to the percutaneous device and a workstationcoupled to the bedside system that includes a joystick configured togenerate a first voltage output signal based on a linear activation ofthe joystick and a second voltage output signal based on a rotationalactivation of the joystick, a joystick cover disposed over the joystickand comprising an upper portion having an electrode plating on an innersurface of the upper portion and a lower portion having an innersurface, a capacitive touch detection circuit coupled to the electrodeplating of the upper portion of the joystick cover, the capacitive touchdetection circuit mounted on the inner surface of the lower portion ofthe joystick cover and configured to detect a proximal change incapacitance in the electrode plating of the upper portion of thejoystick cover and to generate a touch output signal to indicate whethera change in capacitance has been detected, and a signal enable circuitcoupled to the joystick and the capacitive touch detection circuit, thesignal enable circuit configured to generate a linear enable voltageoutput signal and a rotational enable voltage output signal based onwhether a change in capacitance has been detected.

BRIEF DESCRIPTION OF THE DRAWINGS

This application will become more fully understood from the followingdetailed description, taken in conjunction with the accompanyingfigures, wherein like reference numerals refer to like elements inwhich:

FIG. 1 is a perspective view of an exemplary catheter procedure systemin accordance with an embodiment;

FIG. 2 is a schematic block diagram of a catheter procedure system inaccordance with an embodiment;

FIG. 3 is a perspective view of an interlocking system in accordancewith an embodiment;

FIG. 4 is a perspective view of multiple joysticks with interlockingsystems in accordance with an embodiment;

FIG. 5 is a block diagram of an interlocking system in accordance withan embodiment;

FIG. 6 is a block diagram of a signal enable circuit in accordance withan embodiment; and

FIG. 7 is a block diagram of an interlocking system and a joystickactuation detection circuit in accordance with an embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of an exemplary catheter procedure systemin accordance with an embodiment. In FIG. 1, a catheter procedure system100 may be used to perform catheter based medical procedures (e.g., apercutaneous intervention procedure). Catheter based medical proceduresmay include diagnostic catheterization procedures during which one ormore catheters are used to aid in the diagnosis of a patient's disease.For example, during one embodiment of a catheter based diagnosticprocedure, a contrast media is injected onto one or more coronaryarteries through a catheter and an image of the patient's heart istaken. Catheter based medical procedures may also include catheter basedtherapeutic procedures (e.g., angioplasty, stent placement, treatment ofperipheral vascular disease, etc.) during which a catheter is used totreat a disease. It should be noted, however, that one skilled in theart would recognize that certain specific percutaneous interventiondevices or components (e.g., type of guide wire, type of catheter, etc.)will be selected based on the type of procedure that is to be performed.Catheter procedure system 100 is capable of performing any number ofcatheter based medical procedures with minor adjustments to accommodatethe specific percutaneous intervention devices to be used in theprocedure. In particular, while the embodiments of catheter proceduresystem 100 describe herein are explained primarily in relation to thetreatment of coronary disease, catheter procedure system 100 may be usedto diagnose and/or treat any type of disease or condition amenable todiagnosis and/or treatment via a catheter based procedure.

Catheter procedure system 100 includes lab unit 106 and workstation 116.Catheter procedure system 100 includes a robotic catheter system, shownas bedside system 110, located within lab unit 106 adjacent a patient102. Patient 102 is supported on a table 108. Generally, bedside system110 may be equipped with the appropriate percutaneous interventiondevices or other components (e.g., guide wires, guide catheters, workingcatheters such as balloon catheters and stent delivery systems, contrastmedia, medicine, diagnostic catheters, etc.) to allow the user toperform a catheter based medical procedure via a robotic system byoperating various controls such as the controls located at workstation116. Bedside system 110 may include any number and/or combination ofcomponents to provide bedside system 110 with the functionalitydescribed herein. Bedside system 110 includes, among other elements, acassette 114 supported by a robotic arm 112 which may be used toautomatically advance a guide wire into a guide catheter seated in anartery of the patient 102.

Bedside system 110 is in communication with workstation 116, allowingsignals generated by the user inputs of workstation 116 to betransmitted to bedside system 110 to control the various functions ofbedside system 110. Bedside system 110 may also provide feedback signals(e.g., operating conditions, warning signals, error codes, etc.) toworkstation 116. Bedside system 110 may be connected to workstation 116via a communication link 140 (shown in FIG. 2) that may be a wirelessconnection, cable connections, or any other means capable of allowingcommunication to occur between workstation 116 and bedside system 110.

Workstation 116 includes a user interface 126 configured to receive userinputs to operate various components or systems of catheter proceduresystem 100. User interface 126 includes controls 118 that allow the userto control bedside system 110 to perform a catheter based medicalprocedure. For example, controls 118 may be configured to cause bedsidesystem 110 to perform various tasks using the various percutaneousintervention devices with which bedside system 110 may be equipped(e.g., to advance, retract, or rotate a guide wire, advance, retract orrotate a working catheter, advance, retract, or rotate a guide catheter,inflate or deflate a balloon located on a catheter, position and/ordeploy a stent, inject contrast media into a catheter, inject medicineinto a catheter, or to perform any other function that may be performedas part of a catheter based medical procedure). Cassette 114 includesvarious drive mechanisms to cause movement (e.g., axial and rotationalmovement) of the components of the bedside system 110 including thepercutaneous devices.

In one embodiment, controls 118 include a touch screen 124, one or morejoysticks 128 and buttons 130, 132. The joystick 128 may be configuredto advance, retract, or rotate various components and percutaneousdevices such as, for example, a guide wire, a guide catheter or aworking catheter. Buttons 130, 132 may include, for example, anemergency stop button and a multiplier button. When an emergency stopbutton is pushed a relay is triggered to cut the power supply to bedsidesystem 110. Multiplier button acts to increase or decrease the speed atwhich the associated component is moved in response to a manipulation ofcontrols 118. In one embodiment, controls 118 may include one or morecontrols or icons (not shown) displayed on touch screen 124, that, whenactivated, causes operation of a component of the catheter proceduresystem 100. Controls 118 may also include a balloon or stent controlthat is configured to inflate or deflate a balloon and/or a stent. Eachof the controls may include one or more buttons, joysticks, touchscreen, etc. that may be desirable to control the particular componentto which the control is dedicated. In addition, touch screen 124 maydisplay one or more icons (not shown) related to various portions ofcontrols 118 or to various components of catheter procedure system 100.

User interface 126 may include a first monitor or display 120 and asecond monitor or display 122. First monitor 120 and second monitor 122may be configured to display information or patient specific data to theuser located at workstation 116. For example, first monitor 120 andsecond monitor 122 may be configured to display image data (e.g., x-rayimages, MRI images, CT images, ultrasound images, etc.), hemodynamicdata (e.g., blood pressure, heart rate, etc.), patient recordinformation (e.g., medical history, age, weight, etc.). In addition,first monitor 120 and second monitor 122 may be configured to displayprocedure specific information (e.g., duration of procedure, catheter orguide wire position, volume of medicine or contrast agent delivered,etc.). Monitor 120 and monitor 122 may be configured to displayinformation regarding the position the guide catheter. Further, monitor120 and monitor 122 may be configured to display information to providethe functionalities associated with controller 134 (shown in FIG. 2)discussed below. In another embodiment, user interface 126 includes asingle screen of sufficient size to display one or more of the displaycomponents and/or touch screen components discussed herein.

Catheter procedure system 100 also includes an imaging system 104located within lab unit 106. Imaging system 104 may be any medicalimaging system that may be used in conjunction with a catheter basedmedical procedure (e.g., non-digital x-ray, digital x-ray, CT, MRI,ultrasound, etc.). In an exemplary embodiment, imaging system 104 is adigital x-ray imaging device that is in communication with workstation116. In one embodiment, imaging system 104 may include a C-arm (notshown) that allows imaging system 104 to partially or completely rotatearound patient 102 in order to obtain images at different angularpositions relative to patient 102 (e.g., sagittal views, caudal views,anterior-posterior views, etc.).

Imaging system 104 may be configured to take x-ray images of theappropriate area of patient 102 during a particular procedure. Forexample, imaging system 104 may be configured to take one or more x-rayimages of the heart to diagnose a heart condition. Imaging system 104may also be configured to take one or more x-ray images during acatheter based medical procedure (e.g., real time images) to assist theuser of workstation 116 to properly position a guide wire, guidecatheter, stent, etc. during the procedure. The image or images may bedisplayed on first monitor 120 and/or second monitor 122. In particular,images may be displayed on first monitor 120 and/or second monitor 122to allow the user to, for example, accurately move a guide catheter intothe proper position.

In addition, a user of workstation 116 may be able to control theangular position of imaging system 104 relative to the patient to obtainand display various views of the patient's heart on first monitor 120and/or second monitor 122. Displaying different views at differentportions of the procedure may aid the user of workstation 116 toproperly move and position the percutaneous interventional deviceswithin the 3D geometry of the patient's heart. In an embodiment, imagingsystem 104 may be a 2D imaging system. In another embodiment, imagingsystem 104 may be any 3D imaging modality such as an x-ray basedcomputed tomography (CT) imaging device, a magnetic resonance imagingdevice, a 3D ultrasound imaging device, etc. In this embodiment, theimage of the patient's heart that is displayed during the procedure maybe a 3D image. In addition, controls 118 may also be configured to allowthe user positioned at workstation 116 to control various functions ofimaging system 104 (e.g., image capture, magnification, collimation,c-arm positioning, etc.).

Referring to FIG. 2, a block diagram of catheter procedure system 100 isshown according to an exemplary embodiment. Catheter procedure system100 may include a control system, shown as controller 134. Controller134 may be part of workstation 116. Controller 134 may generally be anelectronic control unit suitable to provide catheter procedure system100 with the various functionalities described herein. For example,controller 134 may be an embedded system, a dedicated circuit, a generalpurpose system programmed with the functionality described herein, etc.Controller 134 is in communication with one or more bedside systems 110,controls 118, monitors 120 and 122, imaging system 104 and patientsensors 136 (e.g., electrocardiogram (“ECG”) devices,electroencephalogram (“EEG”) devices, blood pressure monitors,temperature monitors, heart rate monitors, respiratory monitors, etc.).In various embodiments, controller 134 is configured to generate controlsignals based on the user's interaction with controls 118 and/or basedupon information accessible to controller 134 such that a medicalprocedure may be performed using catheter procedure system 100. Inaddition, controller 134 may be in communication with a hospital datamanagement system or hospital network 142 and one or more additionaloutput devices 138 (e.g., printer, disk drive, cd/dvd writer, etc.).

Communication between the various components of catheter proceduresystem 100 may be accomplished via communication links 140.Communication links 140 may be dedicated wires or wireless connections.Communication links 140 may also represent communication over a network.Catheter procedure system 100 may be connected or configured to includeany other systems and/or devices not explicitly shown. For example,catheter procedure system 100 may include IVUS systems, image processingengines, data storage and archive systems, automatic balloon and/orstent inflation systems, medicine injection systems, medicine trackingand/or logging systems, user logs, encryption systems, systems torestrict access or use of catheter procedure system 100, etc.

As mentioned above, controls 118 of user interface 126 may include oneor more joysticks 128 that are used to advance, retract and rotatevarious components and percutaneous devices such as, for example, aguide wire, a guide catheter or a working catheter. If a joystick 128experiences a failure while the catheter procedure system is enabled,one of the devices may move in an unintended manner, for example,movement of the device when a user is not touching the joystick. Aninterlocking system may be provided for joystick 128 to accommodatepotential joystick faults and prevent unintended actuation of a device.FIG. 3 is a perspective view of an interlocking system for a joystick inaccordance with an embodiment. Interlocking system 200 is a capacitivetouch interlocking system and is configured to detect when a user istouching (or making contact with) the joystick and to prevent movementof a percutaneous device if a user is not touching the joystick.Interlocking system 200 is an analog system and does not requiresoftware for operation.

In FIG. 3, a joystick 202 is shown as part of a control console 218. Thecontrol console 218 may be, for example, a part of the user interface126 of the workstation 116 shown in FIG. 1. In an embodiment, joystick202 is an analog joystick configured to generate voltage output signals(V_(JS-X), V_(JS-Z)) proportional to the corresponding linear androtational activation by a user. In one embodiment, the joystick voltageoutput signals range between a supply voltage (V_(DD)) and a groundvoltage (V_(SS)). A zero position or zero velocity reference voltage(V₀) for the joystick 202 may be determined, for example, as half of thesum of the supply voltage and the ground voltage.V ₀=(V _(DD) +V _(SS))/2  Eqn. 1The circuitry for joystick 202 may be located inside of the controlconsole 218. Interlocking system 200 includes a joystick cover 204disposed over the joystick 202. Joystick cover 204 has an upper portionor body 206 and a lower portion or skirt 208. The upper portion 206 ofjoystick cover 204 is disposed over an upper portion or shaft ofjoystick 202 and the lower portion 208 of joystick cover 204 is locatedproximal to a base 216 of joystick 202. In an embodiment, the base 216of joystick 202 may be surrounded by a carbon boot that is coupled toearth ground. The upper portion 206 of joystick cover 204 is plated withan electrode along an inner surface of the upper portion 206. The lowerportion 208 of joystick cover 204 is not plated with an electrode. Theelectrode plating of the upper portion 206 is coupled to a capacitivetouch detection circuit 210 that is positioned on an inner surface ofthe lower portion 208 of joystick cover 204. Parasitic capacitance maybe minimized by positioning the capacitive touch detection circuit onthe inner surface of the non-electrode plated lower portion 208 of thejoystick cover 204 so that the sense electronics are close to theelectrode and at a maximum distance from the ground plane. The electrodeplating of upper portion 206 may be coupled to the capacitive touchdetection circuit 210 using a conductor that is mounted to the joystickcover 204 using a conductive epoxy. For example a multi-conductor wiremay be soldered to the capacitive touch detection circuit 210 andcoupled to the electrode plating on the upper portion 206 of thejoystick cover 204 using silver conductive epoxy. As discussed furtherbelow, capacitive touch detection circuit 210 is configured to detectproximal changes in capacitance from a user touching the joystick 202and joystick cover 204 with respect to earth ground.

The capacitive touch detection circuit 210 is coupled to a signal enablecircuit 212 by a communication link 214, for example, a cable.Communication link 214 is configured to provide power to the capacitivetouch sensing circuit 210 such as for example, a supply voltage (V_(DD))and a ground voltage (V_(SS)) and to carry voltage signals from thecapacitive touch sensing circuit 210 to signal enable circuit 212.Communication link 214 is located proximal to the lower portion 208 ofjoystick cover 204 and proximal to the base 216 of joystick 202. Signalenable circuit 212 may be located, for example, within the controlconsole 218. Signal enable circuit 212 is also coupled to a controller220 for the catheter procedure system, for example, controller 134 shownin FIG. 2 and is coupled to joystick 202 to receive the voltage outputsignals (V_(JS-X), V_(JS-Z)) from the joystick 202. Signal enablecircuit 212 is configured to route the appropriate joystick voltagesignals to the controller 220 based on whether capacitive touch has beendetected by the capacitive touch detection circuit 210. Details of theoperation of the interlocking system 200 are discussed further belowwith respect to FIGS. 5-7.

In an embodiment where more than one joystick is utilized in a catheterprocedure system, an interlocking system 200 may be provided for eachjoystick. FIG. 4 is a perspective view of multiple joysticks withinterlocking systems in accordance with an embodiment. In FIG. 4, acontrol console 318 includes a first joystick 302 with a firstinterlocking system including an electrode plated joystick cover 308, asecond joystick 304 with a second interlocking system including anelectrode plated joystick cover 310 and a third joystick 306 with athird interlocking system including an electrode plated joystick cover312. The first joystick 302 may be used, for example, to control theforward and reverse velocities of a balloon catheter device. The secondjoystick 304 may be used to, for example, control the forward andreverse velocities and the clockwise and counterclockwise angularvelocities of a guide wire. The third joystick 306 may be used to, forexample, to control the forward and reverse velocities and the clockwiseand counterclockwise velocities of a guide catheter. As mentioned above,the first joystick cover 308, second joystick cover 310 and thirdjoystick cover 312 have an electrode plated upper portion and a lowerportion that is not electrode plated.

FIG. 5 is a block diagram of an interlocking system in accordance withan embodiment. A joystick 402 (e.g., joystick 202 shown in FIG. 3) isused to control the linear velocity (forward and reverse) and therotational angular velocity (clockwise and counterclockwise) of adevice. Joystick 402 is configured to generate voltage output signalsproportional to the corresponding activation by a user. In particular, afirst joystick voltage output signal 440 (JS_Linear, V_(JS-X)) isproportional to the corresponding linear activation by a user. A secondjoystick voltage output signal 442 (JS_Rotational, V_(JS-Z)) isproportional to the corresponding rotational activation by a user. Asdescribed above with respect to FIG. 3, a joystick cover 404 is disposedover the joystick 402 and includes an electrode plated upper portion(e.g., upper portion 206 shown in FIG. 3) that is coupled to acapacitive touch detection circuit 410. The electrode plated upperportion of the joystick cover 404 may be coupled to the capacitive touchdetection circuit 410 using, for example, a multi-conductor wire that isattached to the joystick cover 404 using, for example, conductive epoxy.

Capacitive touch detection circuit 410 is configured to detect proximalchanges in capacitance from a user touching joystick 402 and joystickcover 404 with respect to earth ground. Capacitive touch detectioncircuit 410 is coupled to a signal enable circuit 412 and receives powersignals 446 from the signal enable circuit 412, for example, a supplyvoltage (V_(DD)) and a ground voltage (V_(SS)). When touch is detected,the capacitive touch detection circuit 410 generates a touch outputsignal 444 (Touch_Out) that is, for example, equal to its supply voltage(V_(DD)). When touch is not detected, the capacitive touch detectioncircuit 410 generates a touch output signal 444 (Touch_Out) equal to,for example, the ground voltage (V_(SS)). The touch output signal 444 isprovided to the signal enable circuit 412. The sensitivity of thecapacitive detection circuit 410 may be optimized by selecting asuitable sense capacitor (Cs). Preferably, the layout of the capacitivetouch detection circuit 410 is designed to maximize the distance betweenthe touch electrode circuitry from the power and signal planes. Thisminimizes the parasitic capacitance and results in greater capacitivetouch sensitivity.

Both the joystick voltage output voltages (JS_Linear 440 and/orJS_Rotational 442) and the touch output signal 444 (Touch_Out) areprovided to the signal enable circuit 412. Signal enable circuit 412 isconfigured to route the appropriate joystick voltage output signals tothe controller 420 based on whether capacitive touch has been detected(i.e., a user is touching the joystick 402 and joystick cover 404) bythe capacitive touch detection circuit 410. In an embodiment, ifcapacitive touch is detected (e.g., Touch_Out=V_(DD)), then the signalenable circuit 412 sends enable voltage signals, JS_Linear_Enable 448and JS_Rotational_Enable 450, equal to the joystick voltage outputsignals (linear and rotational, respectively) to the controller 420. Theenable voltage signals 448 and 450 may be used by controller 420 tocontrol a device based on the user activation of the joystick 402. Ifcapacitive touch is not detected (e.g., Touch_Out=V_(SS)), then thesignal enable circuit 412 sends enable voltage signals 448 and 450 equalto a predetermined zero velocity reference voltage (V₀) so that a deviceis not actuated.

FIG. 6 is a block diagram of a signal enable circuit 512 in accordancewith an embodiment. In FIG. 6, the touch output signal 544 (Touch_Out)is provided to a low pass filter 560. The low pass filter 560 may beconfigured to filter out high frequency signals, for example, highfrequency heart beat output associated with the capacitive touch outputsignal 544. The low pass filter 560 generates a filtered touch outputsignal 562 (Touch_Out_LP). The filtered touch output signal 562 and thejoystick voltage output signals 540 and 542 (JS_Linear andJS_Rotational) are provided to an analog multiplexer 566. In addition,the zero velocity reference voltage (V₀) 568 is input to the analogmultiplexer 566. The analog multiplexer 566 is configured to route theappropriate voltage output signals based on whether capacitive touch hasbeen detected by the capacitive touch detection circuit 410 (shown inFIG. 5). In one embodiment, if capacitive touch has been detected (e.g.,Touch_Out_LP=V_(DD)), then the analog multiplexer 566 generated enableoutput signals, JS_Linear_Enable 548 and/or JS_Rotational_Enable 550,equal to the joystick voltage output signals 540 and 542, namely,JS_Linear_Enable=JS_Linear and JS_Rotational_Enable=JS_Rotational. Ifcapacitive touch is not detected e.g., Touch_Out=V_(SS)), the analogmultiplexer 566 generates enable output signals, JS_Linear_Enable 548and/or JS_Rotational_Enable 550, equal to the zero velocity referencevoltage (V₀) 568. The outputs 548 and 550 from the analog multiplexer566 are provided to the controller 420 (shown in FIG. 5). In analternative embodiment, if the joystick 402 (shown in FIG. 5) generatesa digital output, the multiplexer 566 may be configured to utilize adigital zero velocity reference signal.

In another embodiment, a joystick actuated detection circuit may also beprovided to determine if the joystick 402 (shown in FIG. 5) is in anactuated state. FIG. 7 is a block diagram of an interlocking system anda joystick actuation detection circuit in accordance with an embodiment.As discussed above with respect to FIG. 5, a signal enable circuit 612routes the appropriate voltage output signals 648, 650 to a controller620 based on whether capacitive touch has been detected by a capacitivetouch detection circuit 610. In the embodiment shown in FIG. 7, thesignal enable circuit 612 may also receive an input (JS_Actuated) 672from a joystick actuated detection circuit 670. The joystick actuateddetection circuit 670 is configured to detect whether the linear axis ofthe joystick 602 (e.g., joystick 202 shown in FIG. 3) or the rotationalaxis of the joystick 602 is outside of a predetermined dead band of thejoystick 602. Accordingly, the joystick actuated detection circuit 670receives as inputs the voltage output signals, JS_Linear 640 andJS_Rotational 642, and monitors the voltage output signals 640 and 642.In one embodiment, if either the linear voltage output signal 640 or therotational voltage output signal 642 deviates more than a dead bandvoltage (V_(dead-band)) from the zero velocity reference voltage (V₀)then the joystick actuated detection circuit 670 generates a joystickactuated output signal 672 (JS_Actuated) that is set to a value of true(e.g., JS_Actuated=1). If the voltages output signals 640 and 642 do notdeviate from the zero velocity reference voltage (V₀) by more than thedead band voltage, then the joystick actuated detection circuit 670generates a joystick actuated output signal 672 (JS_Actuated) that isset to a value of false (e.g., JS_Actuated=0). The joystick actuatedoutput signal 672 may be used by signal enable circuit 612 to identifyif joystick 602 is in a faulty state before actuation. Signal enablecircuit 612 may use the joystick actuated output signal 672 along withthe touch output signal 644 to generate a signal that may be used toactivate an imaging system (e.g., imaging system 104 shown in FIG. 1).For example, a signal may be generated based on the touch output signal644 and the joystick actuated output signal 672 to activate the imagingsystem to begin taking images before a device (e.g., a guide wire, aguide catheter, a working catheter) is actuated.

In one embodiment, the joystick actuated detection circuit 670 mayinclude three subsystems to monitor the joystick voltage output signals640 and 642 and generate the joystick actuated output signal 672. Foreach subsystem, a lower reference voltage (V_(LR)) is set as:V _(LR) =V ₀ −V _(dead-band)  Eqn. 2and an upper reference voltage (V_(UR)) is set as:V _(UR) =V ₀ +V _(dead-band)  Eqn. 3A first subsystem monitors the linear joystick voltage output signal 640to determine if the linear joystick output voltage 640 deviates from thezero velocity reference voltage (V₀) by more than the dead band voltage.If the linear voltage output signal 640 (JS_Linear) is less than theupper reference voltage (V_(UR)), then the (L)ess (Than) (U)pper(R)eference signal (Linear_LT-UR) is set to a value of true (e.g.,Linear_LT-UR=1), otherwise the less than upper reference signal is setto a value of false (e.g., Linear_LT-UR=0). If the linear voltage outputsignal 640 (JS_Linear) is greater than the lower reference voltage(V_(LR)), then a (Greater) (T)han (L)ower (R)eference signal(Linear_GT-LR) is set to a value of true (e.g., Linear_GT-LR=1),otherwise the greater than lower reference signal is set to a value offalse (e.g., Linear_GT-LR=0). A resulting output signal of this linearsubsystem (Linear_Y) is set to a value of true (e.g., Linear_Y=1) ifeither the less than upper reference signal (Linear_LT-UR) or thegreater than lower reference signal (Linear_GT-LR) is false, otherwisethe resulting output signal is set to a value of false (e.g.,Linear_Y=0). These relationships are summarized in Table 1.

TABLE 1 JS_Linear to Linear_Y Logic Table. Condition Linear LT-UR LinearGT-LR Linear_Y JS_Linear ≤ V_(LR) 1 0 1 (outside deadband) V_(LR) <JS_Linear < V_(UR) 1 1 0 (within deadband) V_(UR) ≤ JS_Linear 0 1 1(outside deadband)

A second subsystem monitors the rotational joystick voltage outputsignal 642 to determine if the rotational joystick output voltage 642deviates from the zero velocity reference voltage (V₀) by more than thedead band voltage. If the rotational voltage output signal 642(JS_Rotational) is less than the upper reference voltage (V_(UR)), thenthe (L)ess (T)han (U)pper (R)eference signal (Rotational_LT-UR) is setto a value of true (e.g., Rotational_LT-UR=1), otherwise the less thanupper reference signal is set to a value of false (e.g.,Rotational_LT-UR=0). If the rotational voltage output signal 642(JS_Rotational) is greater than the lower reference voltage (V_(LR)),then a (G)reater (T)han (L)ower (R)eference signal (Rotational_GT-LR) isset to a value of true (e.g., Rotational_GT-LR=1), otherwise the greaterthan lower reference signal signal is set to a value of false (e.g.,Rotational_GT-LR=0). A resulting output signal of this rotationalsubsystem (Rotational_Y) is set to a value of true (e.g.,Rotational_Y=1) if either the less than upper reference signal(Rotational_LT-UR) or the greater than lower reference signal(Rotational_GT-LR) is false, otherwise the resulting output signal isset to a value of false (e.g., Rotational_Y=0). These relationships aresummarized in Table 2.

TABLE 2 JS_Rotational to Rotational_Y Logic Table Rotational RotationalCondition LT-UR GT-LR Rotational_Y JS_Rotational ≤ V_(LR) 1 0 1 V_(LR) <JS_Rotational < V_(UR) 1 1 0 V_(UR) ≤ JS_Rotational 0 1 1In one embodiment, the logic presented in Table 1 and Table 2 may beimplemented using either analog comparators and corresponding digitallogic elements or a mixed signal digital signal processor (DSP) witheither four comparator or analog inputs and two corresponding digitaloutputs for the Linear_Y and Rotational_Y outputs.

A third subsystem generates the joystick actuated output signal 672based on the values of the linear subsystem output signal (Linear_Y) andthe rotational subsystem output signal (Rotational_Y). If either thelinear subsystem output signal (Linear_Y) or the rotational subsystemoutput signal (Rotational_Y) is true, then the joystick actuated outputsignal 672 is set to a value of true (e.g., JS_Actuated=1), otherwisethe joystick actuated output signal 672 is set to a value of false(e.g., JS_Actuated=0). The joystick actuated output signal 672 isprovide to the signal enable circuit 612.

This written description used examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral language of the claims. The order and sequence of any process ormethod steps may be varied or re-sequenced according to alternativeembodiments.

Many other changes and modifications may be made to the presentinvention without departing from the spirit thereof. The scope of theseand other changes will become apparent from the appended claims.

What is claimed is:
 1. An interlocking system for a joystick in acatheter procedure system, the interlocking system comprising: ajoystick configured to generate a first voltage output signal based on alinear activation of the joystick and a second voltage output signalbased on a rotational activation of the joystick; a joystick coverdisposed over the joystick and comprising an upper portion having anelectrode plating on an inner surface of the upper portion and a lowerportion having an inner surface; a capacitive touch detection circuitcoupled to the electrode plating of the upper portion of the joystickcover, the capacitive touch detection circuit mounted on the innersurface of the lower portion of the joystick cover and configured todetect a proximal change in capacitance in the electrode plating of theupper portion of the joystick cover and to generate a touch outputsignal to indicate whether a change in capacitance has been detected;and a signal enable circuit coupled to the joystick and the capacitivetouch detection circuit, the signal enable circuit configured togenerate a linear enable voltage output signal and a rotational enablevoltage output signal based on whether a change in capacitance has beendetected.
 2. An interlocking system according to claim 1, wherein thejoystick is an analog joystick.
 3. An interlocking system according toclaim 1, wherein the capacitive touch detection circuit is coupled tothe electrode plating of the upper portion of the joystick cover using aconductor mounted to the joystick cover using a conductive epoxy.
 4. Aninterlocking system according to claim 1, wherein the signal enablecircuit is coupled to the capacitive touch detection circuit using acommunication link configured to provide a supply voltage to thecapacitive touch detection circuit.
 5. An interlocking system accordingto claim 4, wherein the communication link is further configured toprovide a ground voltage to the capacitive touch detection circuit. 6.An interlocking system according to claim 1, wherein the signal enablecircuit receives a zero velocity reference voltage input.
 7. Aninterlocking system according to claim 6, wherein the linear enablevoltage output signal is equal to the zero velocity reference voltagewhen a change in capacitance is not detected by the capacitive touchdetection circuit.
 8. An interlocking system according to claim 6,wherein the rotational enable voltage output signal is equal to the zerovelocity reference voltage when a change in capacitance is not detectedby the capacitive touch detection circuit.
 9. An interlocking systemaccording to claim 1, wherein the linear enable voltage output signal isequal to the first voltage output signal when a change in capacitance isdetected by the capacitive touch detection circuit.
 10. An interlockingsystem according to claim 1, wherein the rotational enable voltageoutput signal is equal to the second voltage output signal when a changein capacitance is detected by the capacitive touch detection circuit.11. An interlocking system according to claim 1, further comprising ajoystick actuated detection circuit coupled to the joystick and thesignal enable circuit, the joystick actuated enable circuit configuredto detect whether the joystick is in an actuated state and to generate ajoystick actuated output signal.
 12. An interlocking system according toclaim 11, wherein the signal enable circuit generates a control signalfor an imaging system based on the touch output signal and the joystickactuated output signal.
 13. An interlocking system according to claim12, wherein the joystick is used to control a percutaneous device in thecatheter procedure system and the control signal causes the imagingsystem to begin acquiring images before actuation of the percutaneousdevice.
 14. An interlocking system according to claim 1, wherein thecapacitive touch detection circuit is mounted on the inner surface ofthe lower portion of the joystick cover.
 15. An interlocking systemaccording to claim 1, wherein the capacitive touch detection circuit ismounted on the inner surface of the lower portion of the joystick cover.16. A catheter procedure system comprising: a bedside system comprisinga percutaneous device and at least one drive mechanism coupled to thepercutaneous device; and a workstation coupled to the bedside system,the workstation comprising: a joystick configured to generate a firstvoltage output signal based on a linear activation of the joystick and asecond voltage output signal based on a rotational activation of thejoystick; a joystick cover disposed over the joystick and comprising anupper portion having an electrode plating on an inner surface of theupper portion and a lower portion having an inner surface; a capacitivetouch detection circuit coupled to the electrode plating of the upperportion of the joystick cover, the capacitive touch detection circuitmounted on the inner surface of the lower portion of the joystick coverand configured to detect a proximal change in capacitance in theelectrode plating of the upper portion of the joystick cover and togenerate a touch output signal to indicate whether a change incapacitance has been detected; and a signal enable circuit coupled tothe joystick and the capacitive touch detection circuit, the signalenable circuit configured to generate a linear enable voltage outputsignal and a rotational enable voltage output signal based on whether achange in capacitance has been detected.
 17. A catheter procedure systemaccording to claim 16, wherein the signal enable circuit receives a zerovelocity reference voltage input.
 18. A catheter procedure systemaccording to claim 17, wherein the linear enable voltage output signalis equal to the zero velocity reference voltage when a change incapacitance is not detected by the capacitive touch detection circuit.19. A catheter procedure system according to claim 17, wherein therotational enable voltage output signal is equal to the zero velocityreference voltage when a change in capacitance is not detected by thecapacitive touch detection circuit.
 20. A catheter procedure systemaccording to claim 16, wherein the linear enable voltage output signalis equal to the first voltage output signal when a change in capacitanceis detected by the capacitive touch detection circuit.
 21. A catheterprocedure system according to claim 16, wherein the rotational enablevoltage output signal is equal to the second voltage output signal whena change in capacitance is detected by the capacitive touch detectioncircuit.
 22. A catheter procedure system according to claim 16, whereinthe workstation further comprises a joystick actuated detection circuitcoupled to the joystick and the signal enable circuit, the joystickactuated enable circuit configured to detect whether the joystick is inan actuated state and to generate a joystick actuated output signal. 23.A catheter procedure system according to claim 22, wherein the signalenable circuit generates a control signal for an imaging system based onthe touch output signal and the joystick actuated output signal.
 24. Acatheter procedure system according to claim 23, wherein the joystick isused to control the percutaneous device and the control signal causesthe imaging system to begin acquiring images before actuation of thepercutaneous device.
 25. A catheter procedure system according to claim16, wherein the capacitive touch detection circuit is mounted on theinner surface of the lower portion of the joystick.
 26. A catheterprocedure system according to claim 16, wherein the capacitive touchdetection circuit is mounted on the inner surface of the lower portionof the joystick cover.